Shim for springs and the like



K. R. PETERS. SHIM FOR SPRENGS AND THE LIKE. ADPLlcATIoN FILED DEC.2.1921.

Lh Patented May23,1922.

UNITED STATES PATENT orifice.

y Specification of Letters Patent. Patented Maty 23, 4Lllllt22.

Application med December 2, 1921. serial No. lmaar?.

To all whom 'it may concer/n:

.Be it known that I, KARL R. PETERS, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylva-nla, have invented certain new and useful Improvements in a Shim for Springs and the like, of which the following is a specification.

My invention relates to improvements in a friction reducing shim for springs, particularly plate springs for vehicles.

The object of my invention 1s to rovlde a sheet of metal which may be place between the plates of springs for reducing the friction between the plates, and also preventing the surface of the plates of the spring from rusting; a further object of my invention is to provide a sheet or strip of material which will have sufficient stiffness and resilience to retain its shape and position between the spring plates; a further object of my invention is to provide an oil-less friction reducing device for springs which will not lose its anti-friction qualities due to constant Wear, and which will not require any attention after it is installed.

ln carrying out my invention, l provide a friction reducing substance consisting of a soft metal having graphite pressed into its texture. andy l further provide a stiffening plate or stay sheet, of harder metal, for carrying the said soft metal friction reducing substance. The stay sheet of harder metal gives sufficient rigidity to the complete sheet or strip to insure the latter against buckling or twisting. due to the action of the spring plates, which tends to displace anything placed between the plates. soft metal sheet of anti-friction material will be quickly forced out from between the spring plates or crushed by the pressure of said plates. After much experimenting it has been found thata sheet of relatively 'rigid material combined with a coating of softer material, having anti-friction qualities, and made in accordance with my invention, will give theresults desired.

Referring to the accompanying drawing; Fig. l is a perspective view of a portion of a plate spring having my improved friction reducing strips, or shims, interposed between the plates; Fig. 2, is a perspective View of the shim or strip of material showing the different/parts.thereof; and Fig. 3 is a sectional view of the strip of material, drawn on'an enlarged scale.

In the drawings in which like reference v characters referto like parts, 1 represents a strip or sheet of material adapted to be placed between the plates 2 of springs such as are now in generalluse upon vehicles.

The strip or sheet of material l consists of a/central sheet 3 of thin metal, which is relatively hard and sufficiently resilient to retain its shape. The `central sheet 3 is coated with layers 4 and 5 of soft metal, such as Babbitt metal.

The central sheet3 is preferably made of an alloy consisting of copper and tin. Bellmetal has been found to give satisfactory results. rlhese alloys will readily unite with the softer metal by fushion to form the coating surfaces upon the central sheet.

rfhe soft metal coatings 4 and 5 are applied. by fushion, to the surfaces of the central sheet 3. Graphite 6 is then pressed into the layers 4 and 5 of the soft metal, by passing the sheet of combined materials between pressure rolls, in the, presence of flake graphite.

The soft metal coating upon the central sheet 3 will be impregnated with the graphite, and thus form a friction reducing material adapted for the purposes herein set A forth.

The material is made in sheets which are cut into strips of various widths to suit different sizes of springs. The strips may be rolled into a compact bundle and sold in this form. ft may be readily cut into the proper lengths to suit the springs which are to be equipped with the shims or strips of friction reducing material.

Having thus described my invention l claim and desire to secure by Letters Patent:

l. A friction reducing shim adapted to be inserted between plates of springs and the like, consisting of a soft metal having antifriction qualities, and a stay sheet of rela.- tively harder material upon which the said softer metal is applied.

2. A friction reducing shim adapted to lbe inserted between plates of springs and the like, comprising a sheet of soft metal impregnated with graphite.

3. A friction reducing shim adapted to be inserted between plates of springs and the like, comprising a stay sheet of relatively hard and resilient metal, a coating of relatively soft metal upon opposite faces of said sheet, and said soft metal coating impregnated with graphite.

4. A friction reducing device for plate springsand the like, comprising a sheet of relatively hard and resilient metal, layers of babbitt metal a )plied to the opposite surfaces of said sil hated into the babbitt metal.

5. A friction reducing device for plate springs and the like, comprising a sheet of bell metal, babbitt metal coated upon oppo-` site surfaces of the sheet of bell metal and graphite pressed into the babbitt metal.

6. A spring having in 4combination a friction'reducing shim between the plates of the ieet, and graphite impreg-4 spring, said shim consisting of a central sheet of hard resilient material, and'layers of relatively softer material having a friction reducing substance embodied therein applied to the surfaces of the said central sheet.

7. The methodof forming a friction reducing shim, consisting of coating a hard resilient sheet of metal with a relativelyr softer metal and pressing graphite into the surface of the said coating metal.

In testimony whereof I affix my signature.

KARL R. PETERS. 

